Refactored song loading
~9% faster and a bit more stable
Cover loading refactored
Fixed song loading check
Correct use of CoverTextureBig
Merge commit '6be397ac5b9b475b35c008e10a6464f7b33da752' into Better_note_timing

Conflicts:
	VocaluxeLib/Menu/SongMenu/CSong.cs
	VocaluxeLib/Menu/SongMenu/CSongMenuTileBoard.cs
Reflection Fix
Changed Note/Line adding to be sorted in all cases
Using binary search for note timing
Easier sing-note adding
Fix cover load counter
Merge branch 'Better_note_timing' into develop
fixed handling of CoverBig for category covers